Bringing the story into the present day, it’s a mystery-thriller that feels very rooted in cinematic history – part Alfred Hitchcock, part Henri-Georges Clouzot – with its deceptions and double-crosses. It starts in a Swiss clinic, where self-confident photographer Micky (Tuppence Middleton) wakes up after surviving a fire in a French villa owned by her ailing aunt (Frances de la Tour).

Her memory shot with amnesia, her face reconstructed with plastic surgery, she has little clue who she is – even when her aunt’s helper Julia (Kerry Fox) comes to take her back to London. Once there, hooking up with DJ boyfriend Jake (Aneurin Barnard) doesn’t seem to help, but the real shock is learning that her childhood friend Do (Alexandra Roach) died in the fire.

It is Micky’s increasingly twisted relationship with Do that forms the centrepiece to the film, told through extensive flashbacks, as she begins to question her own sanity and identity. It’s all very convoluted, sometimes too much so – and it’s here where the film falls way short of its filmic influences. Amnesia is always a convenient plot device at the best of times and Trap For Cinderella is no Memento.

But Softley is aided by two terrific performances from his leads, Middleton and Roach (who played the young Margaret Thatcher in The Iron Lady), while Kerry Fox is a spiky supporting presence. And, unlike many films these days, at least its brain-teasing will stretch the old grey matter rather than shrink it.